scholarly journals A Baltic heritage in Scotland: Basement terrane transfer during the Grenvillian orogeny

Geology ◽  
2020 ◽  
Vol 48 (11) ◽  
pp. 1094-1098 ◽  
Author(s):  
R.A. Strachan ◽  
T.E. Johnson ◽  
C.L. Kirkland ◽  
P.D. Kinny ◽  
T. Kusky
Keyword(s):  
North Atlantic ◽  
Isotopic Data ◽  
Major Phase ◽  
Gneiss Complex ◽  
Firm Basis ◽  
Grenvillian Orogeny ◽  
Archean Basement

Abstract Archean basement inliers within the Northern Highland terrane (NHT), Scottish Caledonides, have been correlated with the Lewisian Gneiss Complex of the Laurentian foreland. New zircon U-Pb ages indicate that the NHT basement contains evidence for magmatism at 2823–2687 Ma and 1772–1655 Ma. The first group compares with crystallization ages of the foreland Archean gneisses. However, the second group, and a supracrustal unit, formed ∼100–250 m.y. after the youngest major phase of juvenile magmatism and sedimentation in the foreland. Also, there is no indication within the NHT basement of the Paleoproterozoic mafic and felsic intrusions common within the foreland, leading us to conclude that there is no firm basis for correlation of the two crustal blocks. The Caledonian Moine thrust, which separates the foreland and the NHT basement, is thought to have reworked a Grenvillian suture indicated by the presence of the ca. 1100–1000 Ma Eastern Glenelg eclogites. On the basis of the new isotopic data, we propose that the NHT basement was a fragment of Baltica that was emplaced onto Laurentia during the Grenvillian orogeny, representing a further example of basement terrane transfer in the circum–North Atlantic orogens.

Parentage of Archean basement within a Paleoproterozoic orogen and implications for on-craton diamond preservation: Slave craton and Wopmay orogen, northwest Canada

2017 ◽  
Vol 54 (2) ◽  
pp. 203-232 ◽  
Author(s):  
Luke Ootes ◽  
Valerie A. Jackson ◽  
William J. Davis ◽  
Venessa Bennett ◽  
Leanne Smar ◽  
...  
Keyword(s):  
Detrital Zircon ◽  
Crystalline Basement ◽  
Stability Field ◽  
Isotopic Data ◽  
The West ◽  
Slave Craton ◽  
Reasonable Explanation ◽  
Compressional Deformation ◽  
Archean Basement

The Wopmay orogen is a Paleoproterozoic accretionary belt preserved to the west of the Archean Slave craton, northwest Canada. Reworked Archean crystalline basement occurs in the orogen, and new bedrock mapping, U–Pb geochronology, and Sm–Nd isotopic data further substantiate a Slave craton parentage for this basement. Detrital zircon results from unconformably overlying Paleoproterozoic supracrustal rocks also support a Slave craton provenance. Rifting of the Slave margin began at ca. 2.02 Ga with a second rift phase constrained between ca. 1.92 and 1.89 Ga, resulting in thermal weakening of the Archean basement and allowing subsequent penetrative deformation during the Calderian orogeny (ca. 1.88–1.85 Ga). The boundary between the western Slave craton and the reworked Archean basement in the southern Wopmay orogen is interpreted as the rifted cratonic margin, which later acted as a rigid backstop during compressional deformation. Age-isotopic characteristics of plutonic phases track the extent and evolution of these processes that left penetratively deformed Archean basement, Paleoproterozoic cover, and plutons in the west, and “rigid” Archean Slave craton to the east. Diamond-bearing kimberlite occurs across the central and eastern parts of the Slave craton, but kimberlite (diamond bearing or not) has not been documented west of ∼114°W. It is proposed that while the crust of the western Slave craton escaped thermal weakening, the mantle did not and was moved out of the diamond stability field. The Paleoproterozoic extension–convergence cycle preserved in the Wopmay orogen provides a reasonable explanation as to why the western Slave craton appears to be diamond sterile.

scholarly journals Origin(s) and geodynamic significance of Archean ultramafic–mafic bodies in the mainland Lewisian Gneiss Complex, North Atlantic Craton

2020 ◽  
Vol 177 (4) ◽  
pp. 700-717
Author(s):  
George L. Guice ◽  
Iain McDonald ◽  
Hannah S.R. Hughes ◽  
John M. MacDonald ◽  
John W. Faithfull
Keyword(s):  
North Atlantic ◽  
Gneiss Complex ◽  
North Atlantic Craton

Origin of ultramafic–mafic bodies on the Isles of Lewis and Harris (Scotland, UK): Constraints on the Archean–Paleoproterozoic evolution of the Lewisian Gneiss Complex, North Atlantic Craton

2022 ◽  
Vol 369 ◽  
pp. 106523
Author(s):  
George L. Guice ◽  
Sophie R. Miocevich ◽  
Hannah S.R. Hughes ◽  
Iain McDonald ◽  
Kathryn M. Goodenough ◽  
...  
Keyword(s):  
North Atlantic ◽  
Gneiss Complex ◽  
North Atlantic Craton

scholarly journals Paleoenvironment Variability during Termination I at the Reykjanes Ridge, North Atlantic

Geosciences ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 375 ◽  
Author(s):  
Alexander Matul ◽  
Max S. Barash ◽  
Tatyana A. Khusid ◽  
Padmasini Behera ◽  
Manish Tiwari
Keyword(s):  
North Atlantic ◽  
Cold Water ◽  
Younger Dryas ◽  
Depth Range ◽  
Isotopic Data ◽  
Cold Event ◽  
Reykjanes Ridge ◽  
The Holocene ◽  
Carbon Isotopic ◽  
Significant Step

The micropaleontological study (radiolarians and foraminifera) of the sediment core AMK-340, Reykjanes Ridge, North Atlantic, combined with the radiocarbon dating and oxygen and carbon isotopic record, provided data for the reconstruction of the summer paleotemperature across the upper 100 meters water depth range, and paleoenvironments during the Termination I in the age interval of 14.5–8 ka. The response of the main microfossil species to the paleoceanographic changes within the Bølling-Allerød (BA) warming, the Younger Dryas (YD) cold event and final transition to the warm Holocene, was different. The BA warming was well captured by the radiolarian and benthic foraminiferal records, but not the planktic one. The high abundances of the cold-water radiolarian species Amphimelissa setosa as a Greenland/Iceland Sea indicator marked a cooling at the end of the BA and at the start of the YD at 13.2–12.3 ka. The micropaleontological and isotopic data together with the paleotemperature estimates for the Reykjanes Ridge at 60°N document that, after the warm BA, the middle YD ca. 12.5–12.2 ka was the next significant step toward the Holocene warming. The start of the Holocene interglacial conditions was reflected in large representation of the microfossils being indicators of the open boreal North Atlantic environments indicating increasing warmth.

Variation in plagioclase clouding intensity in Matachewan dykes: evidence for the exhumation history of the northern margin of the Sudbury Igneous Complex

2002 ◽  
Vol 39 (6) ◽  
pp. 933-942 ◽  
Author(s):  
J P Siddorn ◽  
H C Halls
Keyword(s):  
Impact Crater ◽  
Regional Metamorphism ◽  
Thin Sections ◽  
Igneous Complex ◽  
Northern Margin ◽  
Sudbury Igneous Complex ◽  
Gneiss Complex ◽  
History Of ◽  
Archean Basement ◽  
Exhumation History

Early Proterozoic Matachewan mafic dykes that cut the Archean Cartier granite – Levack Gneiss Complex north of the Sudbury Igneous Complex (SIC), Canada, are generally metamorphosed to lower amphibolite facies but exhibit locally unaltered plagioclase. These plagioclase feldspars display a clouding similar to that found in the same swarm in the vicinity of the Kapuskasing uplift, about 200 km to the northwest, where the clouding intensity is due to magnetite exsolution and displays a positive correlation with the depth of dyke emplacement. In the Sudbury area, the clouding intensity, obtained by image analysis of thin sections, increases away from the SIC, opposite to the direction of increasing regional metamorphism in the Archean basement. This suggests that the Levack Gneiss Complex north of the SIC was exhumed prior to the intrusion of 2.47 Ga Matachewan dykes and therefore predates the formation of the SIC and associated impact event. The southward tilting of the crust inferred from the plagioclase-clouding data appears to have involved uplift along the Benny Deformation Zone, but the exact age of this deformation is unknown. It may be associated with the 1.8–1.9 Penokean Orogen, 1.85 Ga Sudbury impact crater, or 2.2–2.4 Ga Blezardian Orogen.

scholarly journals Notes on the Foraminiferal Genera <i>Laterostomella</i> De Klasz and Rérat and <i>Streptochilus</i> Brönnimann and Resig

1989 ◽  
Vol 8 (2) ◽  
pp. 215-225 ◽  
Author(s):  
Ivan De Klasz ◽  
Dick Kroon ◽  
Jan E. Van Hinte
Keyword(s):  
North Atlantic ◽  
Morphological Variability ◽  
Isotopic Data ◽  
General Shape ◽  
The North ◽  
The Pacific ◽  
Upper Cenozoic ◽  
The Indian Ocean ◽  
The North Atlantic ◽  
First Time

Abstract. the biserial foraminiferal genera Laterostomella de Klasz &amp; Rérat (1962) and Streptochilus Brönnimann &amp; Resig (1971) have been described from the Miocene of Gabon and from Miocene to Recent levels of the Pacific and Indian Oceans, respectively. Both genera have since been found in the Upper Cenozoic of other regions: Laterostomella at Rockall Bank in the North Atlantic and in Papua-New-Guinea, and modern Streptochilus specimens were collected with plankton nets in the northern part of the Indian Ocean. The apertural characteristics of Laterostomella and Streptochilus show marked similarities as does the general shape of Laterostomella guembeliniformis with some Streptochilus species. However, other Laterostomella species have a very different form and isotopic data indicate that Laterostomella has a benthic and Streptochilus a planktic life habitat. We conclude that both genera are valid. For the first time SEM pictures of Laterostomella species are presented to show morphological variability, surface texture and aperture types.

scholarly journals Hanseatic fish trade in the North Atlantic: evidence of fish remains from Hanse cities in Germany

AmS-Skrifter ◽  
2020 ◽  
pp. 75-92
Author(s):  
Hans Christian Küchelmann
Keyword(s):  
North Atlantic ◽  
Isotopic Data ◽  
High Frequencies ◽  
Size Classes ◽  
Atlantic Trade ◽  
The North ◽  
Large Size ◽  
Fish Remains ◽  
The North Atlantic ◽  
Fish Trade

This paper reviews the evidence for the Hanseatic fish trade in the North Atlantic from the perspective of the consumer sites: the Hanse cities in Germany. Stockfish, the most important good in the North Atlantic trade, are discussed from an archaeozoological perspective. The evidence from Hanse cities accumulated thus far is presented and evaluated. The amount of fish remains analysed from Hanse cities in Germany is still very low, which precludes in-depth research and wider conclusions. Nevertheless, overall patterns appear that are generally consistent with the assumptions of patterns for imported stockfish: high frequencies of Gadidae among the fish remains of coastal Hanse cities, overrepresentation of postcranial skeletal elements, prevailing remains of large size classes, and isotopic data supporting the hypothesis.

scholarly journals Chemostratigraphy of the Snorry drift in the Northern Atlantic

2019 ◽  
Vol 59 (3) ◽  
pp. 469-475
Author(s):  
L. L. Demina ◽  
Ye. A. Novichkova ◽  
N. V. Kozina
Keyword(s):  
North Atlantic ◽  
Geochemical Data ◽  
Western Slope ◽  
Isotopic Data ◽  
The Core ◽  
Sedimentary Matter ◽  
49Th Cruise ◽  
Oxygen Isotopic ◽  
Northern Atlantic ◽  
First Time

On the basis of multi-element chemical analysis and oxygen isotopic data, for the first time the distribution of some geochemical indicators was investigated in the sediment core taken at the Western slope of the Snorry contourite drift (St. AI-3378, North Atlantic) in the 49th cruise of RV "Akademik Ioffe" in 2015. Down the core an asynchronous change in the terrigenous (IRD, Al, Si, Ti, Zr, Cr) and biogenic indicators (CaCO3, Corg) was recorded. Based on multi-element geochemical data, the rhythmic distribution along the core of terrigenous and biogenic sedimentary material has been revealed. Sedimentary matter entered the study area as a result of ice and iceberg unloading, as well as brought by near-bottom currents. The intensity and direction of the near-bottom contour currents seemed to change dramatically with the change of warming and cooling periods during the six marine isotope stages MIS 1–6 (the last 190 ka).

scholarly journals Paleoenvironment Variability during Termination I at the Reykjanes Ridge, North Atlantic

2018 ◽  
Author(s):  
Alexander Matul ◽  
Max S. Barash ◽  
Tatyana A. Khusid ◽  
Padmasini Behera ◽  
Manish Tiwari
Keyword(s):  
North Atlantic ◽  
Cold Water ◽  
Isotopic Data ◽  
Cold Event ◽  
Reykjanes Ridge ◽  
The Holocene ◽  
Carbon Isotopic ◽  
Lower Oxygen ◽  
Significant Step ◽  
Foraminiferal Record

The micropaleontological study (radiolarians and foraminifera) of the sediment core AMK-340, Reykjanes Ridge, North Atlantic, combined with the radiocarbon dating and Oxygen/Carbon isotopic record, provided data for the reconstruction of the summer paleotemperature on the water depth of 100 m, and paleoenvironments during the Termination I in the age interval of 14.5&ndash;8 ka. The response of the main microfossil species on the paleoceanographic changes within the B&oslash;lling-Aller&oslash;d (BA) warming, the Younger Dryas (YD) cold event, and final transition to the warm Holocene was different. The BA warming was well reflected in the radiolarian and benthic but not planktic foraminiferal record. The high abundances of the cold-water radiolarian species Amphimelissa setosa as the Greenland/Iceland Sea indicator marked a cooling at the end of the BA and within the start of the YD at 13.2&ndash;12.3 ka. The micropaleontological and isotopic data together with the paleotemperature estimates for the Reykjanes Ridge at 60&deg; N document that, after the warm BA, the middle YD ca. 12.5&ndash;12.2 ka was the next significant step toward the Holocene warming. Start of the Holocene interglacial conditions was reflected in abundant occurrence of the microfossils being indicators of the open boreal North Atlantic environments and lower oxygen isotope values indicating increasing warmth.

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